Dual purpose desiccant and recovery wheel

Abstract

A thermal energy recovery and humidity control system includes a rotating member including a desiccant material located to rotate across a supply air stream and a return airstream. A variable-speed drive element is operably connected to the rotating member to change a rotational speed of the rotating member to allow for switching between thermal energy recovery operation and humidity control operation of the system. A method of climate control includes rotating a desiccant member across both a supply air stream and a return airstream of a climate control system. The desiccant member is rotated at a first rotational speed to transfer thermal energy from the supply air stream to the return air stream. The desiccant member is rotated at a second rotational speed different than the first rotational speed to reduce humidity of the supply air stream.

The invention claimed is: 
     
       1. A thermal energy recovery and humidity control system comprising:
 a rotating member including a desiccant material disposed to rotate across a supply air stream and a return airstream; and 
 a variable-speed drive element operably connected to the rotating member to change a rotational speed of the rotating member to allow for switching between thermal energy recovery operation and humidity control operation of the system, wherein the rotational speed of the rotating member for thermal energy recovery operation is 45 rpm or higher. 
 
     
     
       2. The system of  claim 1 , further comprising a heat source to heat the return airstream prior to flowing across the rotating member. 
     
     
       3. The system of  claim 1 , further comprising a cooling coil to cool the supply air stream after flowing across the rotating member. 
     
     
       4. The system of  claim 1 , wherein the rotating member is a desiccant wheel. 
     
     
       5. The system of  claim 4 , wherein the desiccant wheel includes a wound silica gel desiccant material. 
     
     
       6. The system of  claim 1 , wherein the rotational speed of the rotating member for humidity control operation is between 0 and 10 revolutions per hour. 
     
     
       7. The system of  claim 1 , wherein the variable-speed drive element is one of a variable frequency drive or gear or belt operated system configured to change the rotational speed. 
     
     
       8. The system of  claim 1 , further comprising a controller in operational communication with the drive element to direct switching between energy recovery operation and humidity control operation. 
     
     
       9. A method of climate control comprising:
 rotating a desiccant member disposed across both a supply air stream and a return airstream of a climate control system at a first rotational speed to transfer thermal energy from the supply air stream to the return air stream, wherein the first rotational speed is about 45 rpm or above; and 
 rotating the desiccant member at a second rotational speed different than the first rotational speed to reduce humidity of the supply air stream. 
 
     
     
       10. The method of  claim 9 , wherein transferring thermal energy from the supply air stream to the return air stream comprises:
 flowing the supply air stream past the rotating desiccant member; 
 transferring thermal energy from the supply air stream to the rotating desiccant member; 
 flowing the return air stream past the rotating desiccant member; and 
 transferring the thermal energy from the rotating desiccant member to the return air stream. 
 
     
     
       11. The method of  claim 9 , wherein reducing humidity of the supply air stream comprises:
 flowing the supply air stream past the rotating desiccant member; 
 transferring moisture in the supply air stream onto the rotating desiccant member; and 
 flowing the return airstream past the rotating desiccant wheel, thereby removing the moisture from the rotating desiccant wheel. 
 
     
     
       12. The method of  claim 11 , further comprising heating the return air stream prior to flowing the return air stream past the rotating desiccant wheel. 
     
     
       13. The method of  claim 11 , further comprising cooling the supply air stream after flowing the supply air stream past the rotating desiccant member. 
     
     
       14. The method of  claim 9 , wherein the second rotational speed is 0 to 10 revolutions per hour.